The present invention relates generally to integrated circuit (IC) designs, and more particularly to a micro-machinery memory device for data storage.
The term “micro-electro-mechanic-system” (MEMS) is used to describe electrically-controlled mechanical parts fabricated using semiconductor manufacturing technology. MEMS technology has been recognized as one of the most promising technologies for its potential in making electro-mechanical devices or machines in scales of micrometers or nanometers. Examples of commonly used micro-machines include switches, actuators, electrical motors, accelerators, etc. Many of those micro-machines can be found in parts for automobile air bags, ink injection components for inkjet printers and other bio-medical devices.
Some micro-machines have been developed to function as memory devices in substitution for conventional non-volatile memory, which may store data by using electrical fuses, anti-fuses or floating gates. The fuse-based memory devices can only be programmed once, and are, therefore, referred to as one time programming (OTP) memory. The floating-gate-based memory devices can be programmed multiple times, and are, therefore, referred to as multiple times programming (MTP) memory.
While the floating-gate-based memory has been frequently used for mass data storage, it has certain drawbacks. A floating gate memory cell stores a data bit by trapping electrons injected through a gate oxide within its floating gate. The gate oxide of the memory cell may fail after many programming cycles. Moreover, since each floating gate memory cell is designed to store only one bit of data, a large memory array is usually required for the memory to store a large number of data.
Among various micro-machines, micro-relays have been used as memory devices for mass data storage. Each micro-relay within the micro-relay memory device has “on” and “off” states that can be used to represent a bit of data. Thus, it can avoid the gate oxide failure problem that may happen to a conventional floating gate memory device. However, the micro-relay memory device is bulky in size, since each of the micro-rely can have a width longer than 100 μm. This renders the application of the micro-relay memory devices impractical.
As such, it is desirable to have a micro-machine memory device for data storage without requiring a large implementation area.